Switching device for use in telephone systems



June 25, 1940. c. c. PUCKEQI'TE ET AL 2,205,491

SWITCHING DEVICE FOR USE IN TELEPHONE SYSTEMS Filed June 11, 1937INVENTORS CHARLES CLARK PucKETTE Z ARTHU-Q WARRINGTON TTY.

Patented June 25, 1940 SWITCHING DEVICE FOR USE IN TELE- PHONE SYSTEMSCharles Clarke Puckette and Arthur Warrington, Stoke, Coventry,Englland, assignors to The General Electric Company Limited, London,

England Application June 11, 1937, Serial No. 147,666 In Great BritainJune 19, 1936 2 Claims.

The present invention relates to switching devices for use in telephonesystems and more especially to that type of device operated by theweight of a receiver or hand microtelephone combination.

Switches of this nature are well known, and their primary purpose is toclose a line loop for signalling when the subscriber removes thereceiver or the like. These switches suffer from certain disadvantages.For instance, it is possible during removal of the receiver from theswitch to cause an impulse to be sent accidentally over the line wires,this impulse positioning a selector if the exchange to which thesubscriber is connected is automatic. In addition, it may be possible byrapid manipulation of the switch to impulse automatic selectors at theexchange without using the automatic dial provided for this purpose.This must be, prevented, in the case of coin box telephones, forexample, as otherwise a connection may be established without payment ofthe usual fee.

According, therefore, to the invention, a switch for use in a telephoneinstrument, operated by the weight of the receiver or the like, iscontrolled by means of a governor mechanism in such manner as to retardthe rate of movement of the switch, preferably in one direction ofmotion only.

In an embodiment of our invention, a cradle switch the plunger of whichis operated by the weight of a hand microtelephone combination, isprovided with a toothed sector which is rotated by the movement of thecradle. The sector engages with a pinion which is coupled by means of aspring to a spur wheel in such a manner that rotation of the pinion inone direction drives the wheel and rotation in the other direction doesnot.

The said wheel engages with a worm, the latter bearing two governorweights each located at the end of a flexible spring. The weights rotateinside a cup, and when a predetermined speed is exceeded, the frictionof the weights against the inside of the cup prevents any appreciablefurther rise in speed.

when the telephone is on the plunger of the cradle switch, certaincontacts inside the instrument are broken. Removal of the telephonecauses the plunger to rise under the action of a spring, the sectordriving the pinion in such a direction as to bring the governormechanism into operation. Thus the said contacts are closed slowly.Replacement of the telephone on the cradle switch causes a rapiddepression of the latter, the pinion revolving freely. Thus it isimpossible for the contacts to be opened and closed suificiently rapidlyto enable impulses to be sent, so that false impulses due to deliberateor unintentional movement of the cradle switch cannot be sent over theline wires to position selectors at the exchange.

The mechanism, comprising the plunger on which the telephone lines whennot in use, the sector, the governor, the contact springs and certainterminals, is preferably made in the form of a single unit which iseasily attached to or detached from the telephone instrument as a whole.I

In order that the nature of the invention may now be better understood,reference should be made to the accompanying drawing which shows anembodiment of the invention.

In the drawing it will be seen that a plunger l of known form isprovided on which the hand microtelephone rests when not in use. Thisplunger is provided with a stem 2 which passes through a collar 3provided on a frame 6. The stem normally slides vertically in the collarand carries at its lower end an insulating tip 5 which opens and closesthe contacts of a spring set 1. This spring set is supported on aportion of the frame 6 and connected to the top part thereof by thepillars 8.

One of the pillars 8 also bears a screw ill on which is pivoted atoothed sector l2 which is moved by an L-shaped member ll fixed to thestem of the plunger by the nut M. This member ll carries a pin l6 whichengages with a slot I! on the sector and rotates the latter when theplunger I is raised or depressed.

The teeth of this sector engage with a small pinion wheel l8 fixed to ashaft which also carries a spur wheel I9, the coupling between thewheels l8 and I9 being by means of a spiral spring clutch of known typewhich permits the wheel I9 to be driven by the sector only when thelatter is moving upwards. Under this condition, the wheel l9, engagingwith a worm 20, drives the centrifugal governor 25, thus limiting thespeed of rotation of the wheel l9 and hence the rate at which theplunger l is enabled to rise on removal of the hand microtelephone.

The plunger is shown in the position which it occupies when the.receiver of the telephone instrument is in use. It is depressed byreplacement of the receiver, and removal of the latter causes theplunger to rise under the influence of the spring 24 which presses atits lower end against a part of the frame 6 and with its upper endagainst the collar 23 which is in engagement with a part of the stem.Connection to the device as a whole is effected by means of theterminals 28, several of these being provided along the centre linesshown. The assembly is fixed to the inside of the base of a telephoneinstrument by screws passing through the holes 29, arrangements beingsuch that removal of the two screws and also of the nut l4 andinsulating tip 5 enables the plunger to be withdrawn upwards from theassembly and the assembly to be withdrawn downwards from the inside ofthe instrument.

By the means above described, the contacts l' are operated by the slowrise of the plunger I a short time after the receiver is removedtherefrom. On replacement of the receiver, however, the spring couplingbetween the wheels I 8 and I9 allows the plunger l to return to a normalposition without any appreciable delay so that no opposition is offeredby it to the weight of the receiver. By these means the shortest impulsethat can be given by depressing the plunger I and allowing it to rise,is approximately to 1 second, this being far too long to permitimpulsing of switches at an exchange to which the instrument isconnected.

We claim:

1. In a cradle telephone having a removable handset, a plunger pushed,downward by the weight of the handset when it is placed on the cradleand moved upward by spring tension when the handset is removed from thecradle, a gear segment pivoted adjacent the plunger, a link connectingthe plunger with the segment so that the segment is moved about itspivot with each movement of the plunger, a governor, and means forlinking the governor with the gear segment to move therewith and retardits action only when the handset is removed from the cradle.

2. In a cradle telephone having a removable handset, a plunger operatedup and down vertically whenever the handset of the telephone is removedor replaced on the cardle, a gear sector pivoted adjacent the plunger, alink pin linking the plunger with the sector and causing correspondingmovement thereof whenever the plunger is moved up or down, a gearrotated back and forth by each movement of the sector, a centrifugalgovernor, and. means for linking the governor to the gear only uponrotation of the gear in one direction.

CHAS. C. PUCKETTE. ARTHUR WARRINGION.

